Prosthetic vascular graft connector

ABSTRACT

Two prostheses each have a tubular sidewall with a terminal portion extending to a connection end. A connector body has first and second terminal portions extending to first and second ends. The connector body terminal portions are respectively surrounded by the prostheses terminal portions. First and second straps respectively circumscribe the prostheses terminal portions to bias the prostheses into engagement with the connector body. The connector body has first and second strap engagement projections respectively captured by apertures in the straps.

CROSS REFERENCE TO RELATED PATENT APPLICATION

This patent application is a divisional of U.S. patent application Ser.No. 10/405,805, entitled “Prosthetic Vascular Graft Connector,” filed onApr. 2, 2003, now U.S. Pat. No. 6,896,688, which relates to and claimspriority to U.S. provisional patent application No. 60/410,205, entitled“Prosthetic Vascular Graft Connector,” that was filed on Sep. 12, 2002.The subject matter of that provisional patent application isincorporated by reference in its entirety herein.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

This invention relates to a connector for interconnecting a firstprosthetic vessel to a second prosthetic vessel, such as duringreconstructive surgery. More particularly, the connector facilitates therapid durable joining of a prosthetic graft to a bodily vessel or organthereby reducing cross-clamp time to enhance recovery.

(2) Description of the Related Art

Vascular reconstructive surgery is utilized to replace portions of bloodvessels damaged by aneurismal and occlusive diseases. One such type ofreplacement is an end-to-end anastomosis where a blood vessel is cut oneither side of a diseased or damaged portion. Prosthetic devices arejoined to the cut ends of the healthy portions of the blood vessel and aconnector joins the prosthetic devices completing a vessel for the flowof blood that by-passes the damaged portion. Among the objectives ofvascular reconstructive surgery is to minimize exsanguination atinterfaces between the blood vessels and the prostheses and atinterfaces between the prostheses, to minimize cross-clamp time (thetime that the blood vessel is externally deprived of blood flow) and tominimize thrombogenicity (the formation of blood clots). The rate of theformation of blood clots tends to increase when flowing blood contactsdifferent materials and when turbulence is introduced into the bloodflow.

Exsanguination is minimized by a tight seal between the vessel and theprosthesis and between interconnected prostheses. Sutures and surgicalstaples are effective to achieve a tight seal between a prosthesis and ablood vessel and are widely used in vascular reconstructive surgery.Sutures and surgical staples are less efficient to form a tight sealbetween two prostheses.

As a replacement to sutures and surgical staples, it is known tointerconnect a prosthesis to a blood vessel with an external clamp. Suchclamps are disclosed in U.S. Pat. Nos. 3,357,432; 3,435,823 and6,402,767, all three of which are incorporated by reference herein intheir entireties. Generally, the prosthesis is inserted into the end ofthe vessel. The prosthesis has a locking structure on an externalsurface, such as detents or barbs. An external clamp or ring then closesabout the vessel portion overlying the locking structure to thereby holdthe vessel firmly in place. Due to the small scale of the vessels,manipulation and accurate placement of the locking structure has, todate, proven difficult.

Another vascular prosthesis connector is disclosed in FR2683141 byThierry Richard and Eric Perouse entitled “Connection device for organvessel prostheses.”

Accordingly, there remains a need for an effective mechanism to rapidlyseal a first vascular prosthesis to a second vascular prosthesis thatdoes not have the disadvantages recited above.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the invention is directed to a vascular prosthesis andconnector assembly. Two prostheses each have a tubular sidewall with aterminal portion extending to a connection end. A connector body hasfirst and second terminal portions extending to first and second ends.The connector body terminal portions are respectively surrounded by theprostheses terminal portions. First and second straps respectivelycircumscribe the prostheses terminal portions to bias the prosthesesinto engagement with the connector body. The connector body has firstand second strap engagement projections respectively captured byapertures in the straps.

In one embodiment of this aspect, the vascular prosthetic surface iseverted about a connector.

In another embodiment of this aspect, a connector is pre-attached toeither one or both ends of vascular prostheses.

Other aspects relate to methods of use and kits containing the subjectconnectors.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a vascular prosthesis connector.

FIG. 2 is a longitudinal sectional view of the connector of FIG. 1.

FIG. 3 is a view of a body of the connector of FIG. 1.

FIG. 4 is a side view of the body of FIG. 3.

FIG. 5 is an end view of the body of FIG. 3.

FIG. 6 is a view of a strap of the connector of FIG. 1.

FIG. 7 is a connector end view of the strap of FIG. 6.

FIG. 8 is a cross sectional view of the strap of FIG. 7 taken along line8—8.

FIG. 9 is a sectional view of the strap of FIG. 7 taken along line 9—9.

FIG. 10 is a longitudinal sectional view of a prosthesis.

FIG. 11 is a view of the prosthesis installed on the connector body.

FIG. 12 is a view of the installed prosthesis of FIG. 11 circumscribedby a strap.

FIG. 13 is a view of a modular aorto-biiliac bypass.

FIG. 14 is an exploded view of the bypass of FIG. 13.

FIG. 15 is a cross-sectional representation of a connector body inaccordance with a second embodiment of the invention.

FIG. 16 is a cross-sectional representation of an assembled vascularprosthesis utilizing the connector body of FIG. 15.

FIG. 17 is a perspective view of the connector body of FIG. 15.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

FIG. 1 shows a connector 20 for connecting a first end of a firstvascular prosthesis 22 to a first end of a second vascular prosthesis 24to by-pass a diseased or damaged portion of a blood vessel. Opposingsecond ends 26, 28 of the first 22 and second 24 vascular prostheses arejoined to cut ends of healthy portions of the blood vessel on eitherside of the diseased or damaged portion. The opposing second ends may bejoined to the blood vessels by conventional methods such as sutures orsurgical staples. Further, use of the connector is not limited to humanreconstructive surgery and may be used in veterinary applications aswell.

An exemplary connector 20 is shown in cross-sectional representation inFIG. 2 and includes a connector body 30, a first strap 32 and a secondstrap 33. The connector body 30 is manufactured from any biocompatiblematerial, including metals, plastics and carbon compounds, for examplepolyethylene or a pyrolytic carbon compound. Preferably, the connectorbody 30 is formed as a unitary molding from an injection molded plastic.The connector body 30 has a generally tubular structure configurationand extends for a length L along a central longitudinal axis 500 betweenfirst rim 36 and second rim 37 that define respective first and secondends of the connector body. The length “L” is dependent on theapplication. For an exemplary aortic anastomosis, “L” is from about 12millimeters to about 14 millimeters. The connector body 30 has an inner(interior) surface 40 with a principal radius R_(I) and an outer(exterior) surface 42 with a principal radius R_(O). For the exemplaryaortic anastomosis, R_(I) is from about 18 millimeters and R_(O) is fromabout 20 millimeters to about 24 millimeters. Typically, R_(O) is about10% greater than R_(I).

A flange 44 extends radially outward from the connector body 30 along acentral transverse plane 502 that divides the body into two halves. Theexemplary flange has an outer radius R_(F) (FIG. 5) that is from about1.5 millimeter a thickness T of from about 0.5 millimeter. As shown inFIG. 2, central transverse plane 502 bisects the flange 44 and separatesfirst connector body portion 46 from second connector body portion 48with each tube portion having a respective length, L_(H1) or L_(H2).L_(H1) is typically, but not necessarily equal to L_(H2).

Along a peripheral surface of the first 46 and second 48 connector bodyportions, offset from the associated rim 36 and 37, a firstcircumferential array of detents 50 and a second circumferential arrayof detents 51 extend radially exterior from the outer surface 42 to anapex 52 at a radius R_(T) (see FIGS. 4 and 5). Described in furtherdetail below, the detents 50, 51 extend upward from the exterior surface42 (see FIG. 2) for a distance effective to engage and retain theprostheses 22, 24. Typically, the detents extend upward from theexterior surface 42 for a distance of about 1 millimeter when formedfrom plastic. Somewhat smaller detents are effective when formed frommetal.

A pair of opposed shafts 60 and 61 shown in FIGS. 2 and 3 extend fromthe flange 44 along an axis 504 shown parallel to the axis 500.Exemplary shafts are of circular section of diameter D_(S) and lengthL_(S) (as shown in FIG. 4). Each shaft is spaced radially outboard fromits associated portion 46, 48 of the connector body 30. Described infurther detail below, the shafts 60, 61 may serve as a handle formaneuvering the connector body and may serve to position the associatedstraps 32 and 33. The shafts enable the prosthesis to be easily andaccurately manipulated even during laparoscopic surgery and otherprocedures with limited access for the surgeon. The shafts may be formedto be removable from the connector body, integral with the connectorbody, or unitary with the connector body, such as when formed as part ofthe same molded piece.

FIG. 6 shows an exemplary strap 32. Depending on positioningcircumstances, such a strap or a mirror image thereof could be utilizedas either of the straps 32 and 33. The strap extends from a proximal end70 to a distal end 72 and has generally inner (interior) and outer(exterior) surfaces 74 and 76. The strap inner surface has a channel 78dimensioned to accommodate the associated detents, (e.g., 50 or 51 ofFIG. 2) and portions of the associated prosthesis (e.g., 22 of FIG. 2)pushed into the channel by such detents. Advantageously, at an inboardside of the strap, there is a generally radial surface 80 joining thesurfaces 76 and 78. At an outboard side of the strap, the strap largelytapers, with the outer surface 76 tapering inward to meet the inwardsurface 74. A blind longitudinal hole or compartment 90 extends from thesurface 80 and for receiving the associated shaft 60, 61.

A channel 100 is provided in the outer surface 76 slightly recessed fromthe compartment 90. A complementary projection 102 is provided extendingradially inward from the inner surface 74 near the distal end 72. In anengaged condition (described below), the channel 100 receives theprojection 102 to lock the strap in a ring-like state. When locked, thestrap prevents relative movement between the prostheses and theconnector body. The locking of the strap is reversible. The strap may bedisengaged by separating the projection from the channel. When the strapis unlocked, the connector may be further manipulated or replaced.Alternatively, other locking methods may be employed.

FIG. 7 is an end view of a strap while FIGS. 8 and 9 illustratedselected portions of the strap in cross-sectional representation.

FIG. 10 shows an exemplary vascular prosthesis 22 having a generallytubular body 120 extending from a first end 122 to an opposing secondend 26. The exemplary body is formed of woven or knitted polyester orother suitable fabric. One preferred polyester is poly (ethyleneterephthalate), such as Dacron (manufactured by DuPont of Wilmington,De.). A major portion of the tubular body 120 has an internal radiusR_(B). The illustrated embodiment includes an enlarged terminal portion126 adjacent the first end 122. The exemplary terminal portion extendsover length L_(T) and, over a major portion thereof, has an internalradius R_(E). The terminal portion is provided for coupling to theconnector 20 with an associated portion of the connector body 30 beingreceived within the enlarged terminal portion 126. The radius R_(E) maybe chosen relative to the radius R_(O) to provide insertion of theconnector with appropriate snugness. The radius R_(B) may be chosenrelative to the radius R_(I) so that, when the prosthesis is installedand carrying blood, the connector does not provide an undue flowrestriction (e.g., R_(I) is chosen to be equal to R_(B)).

In one application of the connector of the invention, a vascularreconstructive surgical procedure entails coupling the second ends 26 oftwo prostheses to healthy portions of the patient's cardiovascularsystem on either side of a diseased or damaged portion and securing theconnector to both first end 122 enlarged terminal portions 126 to couplethe two prostheses. The connector may be pre-secured to one of theprostheses before the surgeon installs such prosthesis. The surgeon mayso pre-secure (pre-install) or the packaged prosthesis may come with theconnector pre-installed. To install each half of the connector to itsassociated prosthesis, the surgeon inserts a connector body portion (46,48 in FIG. 2) into the enlarged terminal portion 126. This may be doneby holding the connector body with a surgical instrument. For example,with reference to FIG. 11, the connector 20 may be held by one or bothof the shafts 60, 61. The prosthesis enlarged terminal portion is thendrawn over the tube portion 46 or 48, advantageously with a slightdegree of stretch so as to firmly engage the detents 50. Advantageouslythe detents are pointed and point outward from the connector body topierce the terminal portion and resist its retraction. With reference toFIG. 12, when the terminal portion is installed, the surgeon theninstalls the associated strap 32. This is done by manipulating the strap32 with the associated shaft 60 and wrapping the strap around theterminal portion 126, finally inserting the projection 102 into thechannel 100 (as illustrated in FIG. 6) to lock the strap 32 in itsinstalled condition.

The connector body is advantageously formed of an appropriate plastichaving sufficient rigidity to withstand the pressure envelope of thepatient's viscera and is further biologically inert within the humanbody. Such plastics are dimensioned to a size effective to withstandarterial pressures of up to 300 millimeters. Preferred plastics includepolyurethane and polyethylene. Other biocompatible materials such asmetals and carbon compounds are also suitable. The connector may bedimensioned for particular applications. Size may be convenientlydesignated by an appropriate diameter or associated radius such as theinterior diameter or its associated radius R_(I). In an exemplary 20 mmembodiment, the radius R_(I) is 10 mm and the radius R_(O) is 11 mm. The20 mm embodiment is near the large end of a size spectrum. Near thesmall end of that spectrum, an exemplary 6 mm embodiment has a radiusR_(I) of 3 mm and a radius R_(O) of 4 mm. The scaling of connector bodywall thickness relative to size will be largely influenced by structuralintegrity considerations. Accordingly, the wall thickness may increaseless than proportionately.

The detent height is R_(T)-R_(O) and is influenced principally by thematerial and thickness of the prostheses. Exemplary woven polyesterprostheses have a wall thickness of 0.3-0.4 mm for such material,exemplary detent height is about twice the prosthesis wall thickness(e.g. about 1-3 times) or approximately 1 mm. The length L_(H) will beinfluenced by structural integrity considerations and by considerationsrelating to the ease of assembling the prosthesis and strap to the bodyweighed against compactness considerations. An L_(H) of about 2.5 mm maybe a practical minimum. For the relatively small exemplary 6 mm size, anL_(H) of about 3 mm may be appropriate. For the relatively largeexemplary 20 mm size, an L_(H) of about 5 mm may be appropriate. Anexemplary flange thickness T is 1 mm. The detents advantageously fallalong the outboard half of the length L_(H). The handle shaft lengthL_(S) is advantageously about half L_(H) to avoid clearance problemsrelative to the detents.

An exemplary strap is molded of an appropriate plastic that isbiologically inert within the body. Suitable plastics includepolyethylene or polyurethane with a thickness of about 3 millimeters. Anexemplary principal thickness T_(S) is about 2 mm and an exemplary widthW_(S) is equal to L_(H). Advantageous values of T_(S) may be relativelyinsensitive to size. The flange radius R_(F) is advantageously the sameas the outer radius of the installed straps.

FIG. 13 shows a flow-splitting prosthesis (“flow splitter”) 200installed in an aorto-biiliac bypass establishing communications betweena patient's aorta 600 and iliac arteries 602 and 604. The flow splitter200 is generally Y-shaped, having a leg or trunk 202 and a pair of firstand second arms or branches 204 and 206. The flow splitter 200 iscoupled to the arteries by respective connection prostheses 202, 204,and 206. The flow splitter 200 is coupled to the prostheses 202, 204,and 206 via respective couplers 208, 210, and 212. Except as otherwisedescribed, these couplers may be otherwise similar to the connector(illustrated in either FIG. 2 or FIG. 15 as described below) and havesimilar interaction with the associated prostheses.

Prior to surgery, the sizes of the prostheses 202, 204, and 206 will beselected based upon medical imaging. Most key is the cross-sectionalarea characterized by a diameter or radius. Length may also be relevantand may be used to either select a particular prosthesis or cut aprosthesis to a particular length. By way of example, the prostheses202, 204, and 206 may have nominal diameters of eighteen, eight and tenmm, respectively in one common size combination.

With reference to FIG. 14, in an exemplary surgical procedure, thebodies of the couplers 208, 210, and 212 are preinstalled on associatedends of the prostheses 202, 204, and 206. They may be so installed withrespective straps 214, 216, and 218. Alternatively, they may be securedby other means for example when only the other half of each connectorbody is adapted for receipt of such straps.

The components illustrated in FIG. 14 may be provided in kit form. Forexample. Prostheses 202, 204 and 206 are supplied from a medical supplyhouse with connectors 208, 210 and 212 pre-attached. The kit wouldfurther include a required prostheses 200 and a number of locking straps222, 224 and 226. It is preferred, but not required, that the connectors208, 210 and 212 would be of similar configuration such that lockingstraps 222, 224 and 226 are interchangeable.

The surgeon secures the connection prostheses 202, 204, and 206 to theirassociated arteries. In the illustrated example, the connectionprosthesis 202 is surgically stapled to the aorta 600 in an end-to-endanastomosis. Suturing is an alternative. The connection prosthesis 204is also secured to its iliac artery 602 via an end-to-end anastomosissuch as via stapling or suturing. The connection prosthesis 206 isconnected to its iliac artery 604 via an end-to-side anastomosis such asvia suturing or stapling.

After installation of the connection prostheses 202, 204, and 206, thesurgeon may install flow splitter 200. If the coupler bodies arepreinstalled at the factory to their associated connection prostheses202, 204, and 206, rings 222, 224, and 226 may be prepackaged with suchconnection prostheses. Alternatively, such rings may be prepackaged withthe flow splitter 200 or otherwise provided. With the connectionprostheses 202, 204, and 206 installed, the surgeon may finally size theflow splitter 200 by removing distal lengths of one or more of the trunk192, first branch 194, and second branch 196 to define final ends 230,232, and 234, respectively. Terminal portions adjacent to these ends arein turn placed by the surgeon over associated end portions of the bodiesof connectors 208, 210, and 212 and secured with straps 222, 224, and226. Blood flow is then reestablished and the surgery site closed.

In accordance with another embodiment of the invention, an alternativeconnector 20′ is illustrated in cross-sectional representation in FIG.15. A first prosthesis 22 extends through an interior bore 302 ofconnector body 300. An end portion 303 of the first prosthesis 22 iseverted 304 and folded back over a first rim 306 of the connector body300 and engaged along an exterior surface of the connector body, such asby detents 308. As illustrated in FIG. 16, a second prosthesis 24intended to be joined to the first prosthesis 22 has an enlargedterminal portion 309 extended over the end portion 303 of the firstprosthesis and engaged on detents 308. When properly positioned, strap310 is circumscribed about the connector body 300 to firmly retain theconnector in place. Throughout the assembly, handle 312 is used tomanipulate the connector body.

The embodiment of FIG. 15 is further illustrated in perspectiverepresentation in FIG. 17 where first prosthesis 22 has been extendedthrough the interior bore of connector body 300 and an end portion 303everted and engaged on detents 308. Handle 312 provides ease ofmanipulation.

In the embodiment illustrated in FIGS. 15-17, the surface contacting theblood remains that of the prostheses, rather than a transition to theinterior bore of the connector. Avoiding the changing of surfacechemistry reduces the risk of thrombosis inherent when the chemistry ofthe surfaces contacted by the blood changes. Thrombogenicity is furtherreduced by a reduced turbulence imparted into the blood flow.

One or more embodiments of the present invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention. Forexample, the connectors may be tailored for a variety of general orspecific applications. Accordingly, other embodiments are within thescope of the following claims.

1. A vascular connector for joining a first tubular vessel to a secondtubular vessel, comprising: a connector body with a first connector bodyportion for engaging a first end of said first tubular vessel and asecond connector body portion for engaging a first end of said secondtubular vessel, said connector body extending for a length along alongitudinal axis; an extension projecting radially outward from saidconnector body and having opposing shaft portions extendingsubstantially parallel to said longitudinal axis; a first locking strapfor circumscribing said first connector body portion and said extensionthereby preventing movement of said first tubular vessel relative tosaid connector body; and a second locking strap for circumscribing saidsecond connector body portion thereby preventing movement of said secondtubular vessel portion relative to said connector body.
 2. The connectorof claim 1 wherein a first radial array of detents extends outward froman exterior surface of said first connector body portion and a secondradial array of detents extends outward from an exterior surface of saidsecond connector body portion.
 3. The connector of claim 2 whereindetents of said first radial array of detents outwardly terminate at anapex and said detents are effective to pierce and retain a wall of saidfirst tubular vessel.
 4. The connector of claim 2 wherein said extensionhas a length effective for grasping to facilitate manipulation of saidconnector body.
 5. The connector of claim 4 wherein said extension isintegral with said connector body.
 6. The connector of claim 5 whereinsaid extension is unitary with said connector body.
 7. The connector ofclaim 4 wherein said extension is removable from said first connectorbody portion.
 8. The connector of claim 4 wherein said second tubularconnector is a mirror image of said connector body.
 9. The connector ofclaim 4 wherein said first locking strap is locked by engaging a firstend thereof into a second end thereof.
 10. The connector of claim 9wherein said first locking strap is adapted so that locking isnon-permanent and said first end thereof may be disengaged from saidsecond end thereof.
 11. The connector of claim 10 wherein said first endthereof includes a projection that engages a channel formed in a secondend thereof.
 12. The connector of claim 9 wherein said first tubularvessel and said second tubular vessel are both vascular prostheses. 13.The connector of claim 10 wherein said first locking strap is removablefrom said connector when unlocked.